I don't think there is just an "IF" thing to add handicaps to anything.
Having said that, I might be a good idea to specify what program / application you talk about, as there are a lot of Imsim programs/ apps these days.
The thing that you can do (as Ballast/Intake restrictions are reported by insim) is check them when a car joins the track, and if they're incorrect, spectate the driver and tell them the ballast/intake that they need to have.
I'm sure everyone that knew anything about this saw it and didn't say anything because its not fair to show their work to the public like that. No one is obligated to answer. So you don't have to bump this post. And they mostly explained to you how you should do it.